X Maths Chapter 1 - Arithmetic Sequences

Arithmetic Sequence 5

Ans)
The next two lines of this pattern will be,
34 37 40 43 46
49 52 55 58 61 64

The numbers of the given pattern are in the order,

4, 7, 10, 13, . . . . . . . ( d = 7 − 4 = 3)
( This is an arithmetic sequence obtained multiplying the

natural numbers by 3 and adding 1 .)

Algebraic form is 3n + 1

Last number in the 19th line = 3 × 19 x 20 + 1 Last number in the
2 19th line of the
pattern of natural
= 570 + 1 numbers is ,

= 571 19 x 20
2

First number in the 20th line = 571 + 3 = 574 ( d is 3)

Last number in the 20th line = 3 × 20 x 21 +1
2

= 630 + 1

= 631

Cecilia Joseph, St. John De Britto’s A . I. H. S, Fortkochi